Forage harvester



sept. 19, 1967 B. D. SCHWALM 3,341,929

FORAGE HARVESTER Original Filed Aug. lO, 1965 2 Sheets-Sheet 1 kle In t INVENTOR. 38 BRUCE D. scHwALM A TT NE Y Sept. 19, 1967 B. D. SCHWALM 3,341,929

FORAGE HARVESTER Original Filed Aug. l0, 1965 2 Sheets-Sheet 2 INVENTOR. BRUCE D. SCHWALM United States Patent O f ABSTRACT F THE DISCLOSURE A fixture for assembling a helical spring on a circular shaft and having a hollow cylindrical body for receiving and holding the spring against rotative movement, and a collar rotatably mounted on the cylindrical body for applying a torsional load on the spring.

This application is a division of copending application Ser, No. 478,549, iled Aug. 10, 1965, now Patent No. 3,268,268.

This invention relates generally to forage harvesters. More particularly, 4the invention relates to a discharge spout control for a forage harvester.

A forage harvester, of the type to which the invention is particularly applicable, comprises generally a pick-up mechanism for delivering crop material onto an apron conveyor, feed rolls which receive material from the conveyor and deliver it to be chopped, and a cutter uni-t which functions to comminute the crop material and discharge it at a high velocity to a trailing wagon. The forage harvester cutter in performing the chopping function cooperates with a stationary shear bar mounted along the periphery of the housing. As the material leaves the cutter, it ente-rs a vertically and rearwardly extending discharge spout, having an upper portion which is pivotally and adjustably mounted so that crop material can be directed to a plurality of points in a trailing wagon.

One means which has been employed for adjustably positioning the discharge spout in a worm gear arrangement comprising a worm ring mounted on the discharge spout, a worm mountedv generally tangential to the worm ring on the spout support, and a rod or other means for driving the worm which extends forwardly to a position on the forage harvester where it can be reached by the operator. The main disadvantage is a worm gear adjusting means is that it is relatively expensive. Attempts have been made to manufacture inexpensive worm gears; however, the diiculty has been in making an inexpensive gear which has the necessary wear characteristics. In one known design, a worm is formed by mounting a helical spring on a smooth shaft and fixing the spring ends to the shaft. When the spring is so mounted, the coils` are movable for a limited amount in an axial direction, but the spring cannot turn on the shaft because of the fixed ends. This design, although satisfactory from the cost standpoint, has two main disadvantages. First, because of the axial movement of the spring coils, there is an undesirable cushioning effect and a considerable lag between actuation of the worm and movement of the worm ring. Second, it has been found that after some use the coils fail or become misaligned and the coil ends tend to work loose from the shaft.

Accordingly, one object of this invention is to provide a forage harvester of the character described with a novel and improved forage harvester spout control.

Another object of this invention is to provide a spout control of the character described that is efficient, simple, and inexpensive.

3,341,9'29 Patented Sept. 19, 1967 ICC Another object of this invention is to provide an inexpensive and extremely durable worm gear.

A further object of this invention is to provide a novel method of making a worm to be used in a forage harvester spout control.

A still further object of this invention is to provide a novel fixture for installing a helical coil on a shaft.

Other objects of this invention will be apparent hereinafter from the specification and from the recital in the appended claim.

In the drawings:

FIG. 1 is a perspective view of the forage harvester spout control constructed according to this invention and showing the worm gear;

FIG. 2 is a plan view of the spout control and showing one of the clamping means;

FIG. 3 is a front elevational view showing the worm and worm ring;

FIG. 4 is a cross section taken on line 4 4 -of FIG. 3;

FIG. 5 is a detailed view of the worm with the helical spring shown in section;

FIG. 6 is in part an elevational view and in part a sectional View of the special fixture employed in assembling the helical spring on the shaft;

FIG. 7 is a section on line 7-7 of FIG. 6;

FIG. 8 is a plan view of FIG. 6 and showing the positions of the handle and linger in dot-and-dash lines when the helical spring is in an expanded position;

FIG. 9 is a view similar to FIG. 6, but showing the helical spring in an expanded position and the worm shaft in abutment against the lower arm.

Referring now to the drawings by numerals of reference and particularly to FIGS. l and 2, 10 denotes a forage harvester discharge portion having a support 12 and a discharge spout 14. Carried on the discharge spout, and fixed thereto by welding or other means, is a collar or worm Wheel 16. Operatively engaging the worm wheel is a worm 18 driven by shaft 20 which extends forwardly to the harvester tongue area for operation by the farmer.

A radially extending flange 22 projects from the upper portion of support 12, and a sleeve 24 extends upwardly from this flange. Discharge spout 14 is mounted over sleeve 24 with worin wheel 16 resting on ange 22. A plurality of generally vertically extending slots 25 are formed in the outer periphery of wheel 16- for engagement with worm 18. Two side clamps 26 and 27 and a rear clamp 28 serve to hold the discharge spout in position on the support 12. Rear clamp 28 is removably held on flange 22, by bolts 30 and clamps 26 and 27 have threaded studs (not shown) which are connected to flange 22. Worm 18 is journalled in a pair of bearings 32 which are bolted to a support 34 aiiixed to radially extending flange 22. Shaft 20 is connected to worm 18 through a conventional type universal joint 36. Wo-rm 18 can be adjusted radially inwardly or outwardly with respect to the worm Wheel 16 by loosening bolts 38 and sliding bearings 32 on support 34 within the limits of slots 40.

As best shown in FIG. 5, worm 18 is formed with two end portions 41, 42 of the same diameter and a medial portion 44 of a greater diameter. A helical groove 46 is formed in the outer periphery of medial portion 44 and a helical spring 48 is mounted therein. The radius of curvature of the groove is equal to the radius of the spring wire and the depth of the groove is substantially less than these radii. The pitch of helical spring 48 is substantially equal to the pitch of groove 46, and the inside diameter of the spring in its unexpanded condition is less than the minor or smallest diameter of groove 46. Thus, spring 48 is held in groove 46 by tension and it is further secured to the shaft by welding its ends` to portion 44 (see FIG. 3).

An important feature of this invention is the method and apparatus used in making worm 18. In forming the worm, a piece of low-grade steel stock of appropriate length is selected having a circular cross section and a diameter equal to that of intermediate portion 44. The stock is first placed in a lathe where end portions 41, 42 are formed and helical groove 46 is cut in portion 44.

A special fixture 50, as shown in FIGS. 6-9, is used to mount helical spring 48 in groove 46 on the shaft portion 44.. Fixture t) comprises a vertical support 51 having upper and lower horizontal arms 53 and 55, a vertically extending hollow cylinder 52, and a cylindrical element 58 mounted on the upper end of cylinder 52. Lower arm 53 is removably attached to support 51 by screws 59. An abutment 56 on the lower portion of cylinder 52 has a hole 57 for receiving one end of spring'48. A set screw 54 engages a threaded hole in cylinder 52 and serves to hold the spring in the abutment. An radially inwardly extend ing finger 60 on element 58 contacts the other end of spring 48. A handle 62 is provided to rotate element 58 about the axis of cylinder 52.

In mounting helical spring 48 on the shaft, cylindrical element 58 is removed from cylinder 52 of fixture 50 and spring 58 is inserted in cylinder 52 with the spring lower end in hole S7 of abutment S6. Set screw 54 is then drawn down to securely hold the lower end of spring 48. Cylindrical element 58 is then placed on cylinder 52 with finger 60 in contact with the upper end of spring 48. Handle 62 is then moved approximately 45 degrees in a clockwise direction from its solid-line position (see FIG. 8) to the position shown in dot-and-dash lines and ringer 60 is correspondingly moved. The movement of finger 60 against the upper end of spring 48 applies a torsional load on the spring which results in the spring being expanded from the position shown in FIG. 7 to the position shown in FIG. 9. With spring 48 in its expanded position, the worm shaft is easily threaded into the spring and into abutment with lower arm 53 on fixture 50. The torsional load is then released to seat the spring 48 in groove 46. The only remaining step is completing the worm is to weld the two ends of spring 48 to the shaft in a conventional manner.

The desired radial position of the discharge spout is determined by the position of the trailing wagon. It is, of course, understood that spout 14 terminates in a conventional substantially horizontal deflector (not shown) at its uppermost point which directs the crop material away from the forage harvester and towardthe trailing wagon. The operator changes the direction of discharge by turning a handle (not shown) on the forward portion of the harvester which rotates shaft 20 and worm 18 to drive worm ring 16 on discharge spout 14.

It will be apparent from the foregoing discussion that a simple, inexpensive, and efcient discharge spout control is achieved by the disclosed invention. The worm gear arrangement provides a positive drive means and has proven to be resistant to wear and failure.

While this invention has been described in connection with a particular embodiment thereof, it will be understood that it is capable of modication, and this application is intended to cover any variations, uses, or adaptations following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains, and as fall within the scope of the invention or the limits of the appended claim.

Having thus described my invention, what I claim is:

A ixture for assemblying a helical spring on a circular shaft having a helical groove on its outer periphery and` wardly extending handle on said element for turning said.

element, an abutment and a set screw on said cylinder and adjacent said cylinder lower end for fixedly holding the other end of said spring, and when said spring is iixed in said cylinder and a torsional load is applied to said spring one end by said cylindrical element the internal diameter of said spring is increased sufliciently to permit said shaft to be easily screwed into said spring.

References Cited UNITED STATES PATENTS 1,231,643 7/1917 Parnall 74-458 1,866,783 7/ 1932 White 29-227 3,186,082 6/ 1965 Ulrich 29-456 WILLIAM FELDMAN, Primary Examiner.

I. C. PETERS, Assistant Examiner. 

